It has been proposed to fit a four-wheeled vehicle with a rear wheel steering control system in addition to a more conventional front wheel steering system for the purpose of improving the driving stability of the vehicle. Typically, in association with each rear wheel is provided an electric linear actuator having an output rod that can be selectively extended and retracted so that the two rear wheels may be steered individually. See Japanese patent laid open publication No. 9-030438, for instance.
The linear actuator may be advantageously incorporated into one of the lateral arms that form a part of the wheel suspension system of the corresponding rear wheel. In such a case, changing the toe angle of the rear wheel is effected by changing the length of such a lateral arm. Therefore, as the toe angle of the rear wheel is changed, the geometry of the wheel, in particular the tread of the rear wheels, changes at the times of bump and rebound, and this may adversely affect the ride quality of the vehicle.